Fan



Feb. 17,1942. HQNERKAMP 2,273,756

. FAN- I Q Filed Oct. 18, 1959 4 Sheets-Sheet l Patented Feb. 17,1942

FAN

Friedrich Honerkamp, New York, N. Y., assignor to Anemostat Corporation of America, a. corporation of Delaware Application October 18, 1939 Serial K0. 300,073

13 Claims. (01. 170-171) This invention relates to impellers or fan s, ca-

pable of general use but particularly intended for the circulation of air, and has particular reference to an impeller or fan of the type disclosed inthe application of Franz J. Kurth and myself, Serial No. 107,762, filed October 27, 1936, (now Patent No. 2,153,576, dated April 11, 1939) and represents acarrying forward of the inven-v tion disclosed'in said prior application.

One important object of the invention is to provide an impeller or fan embodying a construction such that, for any given number of blades of any given length and width rotating at any given speed, the propulsion efiect is exceptionally high.

Another'important object of the invention is to provide an impeller or fan embodying blades so designed as to produce substantially equal propulsion efiects throughout their lengths, or at least to produce exceptionally strong propulsion efiects in the regions of their inner ends commensurate with the propulsion effects produced by their outer end portions.

Another important object of the invention is to provide an impeller or fan for use in special instances and embodying blades so designed as to direct air toward a prolongation of the axis of the impeller or fan, as distinguished from directing the air parallel to said axis or outwardly with respect thereto.

Another special object of the invention is to provide a novel method of manufacturing impellers or fans of the present general type in a simple, practical and economical manner.

With the foregoing and other objects in view, which will become more fully apparent as the nature of the invention is better understood, the same consists in an impeller or fan embodm'ng the novel combination and arrangement of features, and in the novel production method, as will be hereinafter more fully described, illustrated in the accompanying drawings and defined in the appended claims.

In the accompanying drawings, wherein like characters of reference denote corresponding parts in related views:

Figure 1 is an end elevation of an impeller or fan constructed in accordance with one practical embodiment of the invention.

Figure 2 is a plan view of the impeller or fan shown in Fig. 1.

another alternative embodiment of the inven- Figure 5 is a plan view, of the impeller or fan shown in Fig. 4.

Figure 6 is another view similar to Fig. 1 illustrating another alternative embodiment of the invention.

Figure 7 is a plan view of the impeller or fa shown in Fig. 6. a

Figure 8 is a plan view illustrating the manner of cutting a blank of sheet material in accordance' with the first step of the present method of forming a fan of the present type; and

Figures 9 and 10 are plan views illustrating subsequent steps of the present method.

Referring to the drawings in detail, first with particular reference to the embodiment of the invention illustrated in Figs. 1 and 2, A designates a cylindrical hub and B designates blade units carried by said hub and equidistantly spaced apart therearound.

In accordance with the invention each blade unit B comprises a pair of blades I0 and H which may be formed in any suitable manner. For example, said blades may be molded from any suitable material or they may be formed from elongated strips of sheet metal or other suitable sheet material by bending said strips intermediately upon themselves along lines at right angles thereto into approximately V-shape. In any event, the blades of each pair are connected together at their outer ends and diverge the hub A and also circumferentially around said hub, as illustrated in Fig. 2' of the drawings. The result is that the said blades of each pair are disposed diagonally with respect to a plane at right angles to the axis of the hub, or, in other words, diagonally with respect to the plane of rotation of the fan. Moreover, the inner ends of the blades l0 and H of adjacent blade units B are alined, or approximately alined, with each other longitudinally of the hub A.

Because of the described dual fan blade arrangement in which the blades at the receiving end of the fan slope outwardly toward the blades at the delivery end of the fan and the blades at the delivery end of the fan slope outwardly toward the blades at the receiving end of the fan, and in which the spaces between the blades of each pair are closed at their outer ends,

to the plane of rotation of the fan, with the blades l and H of adjacent blade units alined, or approximately alined, longitudinally of the hub A, and the blades I0 alined with each other annularly of the fan and offset, longitudinally of the fan, relative to the blades H which likewise are alined with each other annularly of the fan, rotation of the fan results in air first being acted upon by the blades at the receiving end of the fan and having an initial impulse imparted thereto, and then being acted upon by the blades at'the delivery end of the fan and having a final impulse or boost imparted thereto. At the same time, due to the spaces between the blades of each unit being closed at their outer ends, the air acted upon .by the blades at the receiving end of the fan is restrained against outward flow. The ultimate result is that for a fan having any given number of blades of any given length and width rotating at any given speed, the propulsion effect is exceptionally high.

According to the embodiment of the invention illustrated in Fig. 3 of the drawings, two sets ofblade units 3*, 3*, each duplicating the single set.of blade units B shown in Figs. 1 and 2, are combined with each other in a novel manner. In other words, the two sets of blade units B are spaced apart longitudinally of the fan, preferably, but not necessarily, with corresponding blades of corresponding units of the two sets alined with each other longitudinally of the fan and, in any event, with the inner blades of the units of each set disposed, longitudinally of the fan, preferably midway, or approximately midway, between the blades of the units of the other set. In this case the operation of the fan is the same as in the case of the fan shown in Figs. 1 and 2, but due to the two sets of blade units the propulsion effect of the fan is greatly increased.

According to the embodiment of the invention illustrated in Figs. 4 and of the drawings the construction is similar to the construction illustrated in Figs. 1 and 2 in that a hub A is provided with blade units B each comprising a pair of blades Ill and H disposed relative to each other and to the hub A in the same general manner as the blades I0 and ll' of the Figs. 1 and 2 construction are disposed relative to each other and to the hub A. However, as distinguished from the Figs. 1 and 2 construction wherein the blades l0 and I I have the same diagonal relationship or pitch throughout their lengths to the plane of rotation of the fan, the blades l0, ll of the Figs. 4 and 5 construction have different diagonal relationships or pitch, at points spaced along their lengths, to the plane of rotation of the fan. In other words, the angularity or pitch of the blades Ill ll with respect to the plane of rotation of the fan progressively increases toward the inner ends of said blades. Thus, since the velocity of the blades progressively increases toward their outer ends and progressively decreases toward their inner ends, and since the pitch of said blades progressively decreases toward their outer ends and progressively increases toward their inner ends, the result is that the pressure effect of the blades upon the air progressively decreases toward the outer ends of the blades and progressively increases toward the inner ends of the blades. Consequently, the air flow produced by and in which the blades are disposed diagonally the blades is approximately uniform throughoutthe length of the blades.

As further distinguished from the blade arrangement of the Figs. 1 and 2 construction, the blades l0, ll of adjacent blade units of the Figs. 4 and 5 construction are not-alined longitudinally of the fan. On the contrary, the leading edges of the leading blades and the trailing edges of the trailing blades of adjacent blade units B are, at their inner ends, disposed approximately in common radial planes and approximately in a single plane parallel to the plane of rotation of the fan. In other words, the leading edges of the leading blades and the trailing edges of the trailing blades of adjacent blade units B are disposed approximately in corner to corner relationship at their inner ends where they intersect the hub A Annularly of the fan the leading blades are alined with each other and the trailing blades are alined with each other, but the leading blades are offset longitudinally of the fan relative to the trailing blades in the direction of flow of the impelled air. Thus, the air impulsed by the trailing blades is given a final impulse or boost by the leading blades. This will be apparent from Fig. 5 of the drawings wherein the leading and trailing blades are designated as Ill and! l respectively, and wherein the arrows a and b indicate, respectively, the direction of rotation of the fan and the direction of the air flow produced by the fan.

According to the embodiment of the invention illustrated in Figs. 6 and 7 of the drawings, wherein the hub is designated as A and the blade units as 3*, the construction is the same as illustrated in Figs. 4 and 5, except that the blades, designated as lll I I, are peculiarly shaped to direct part of the impelled air toward a prolongation of the axis of rotation of the fan. In other words, the pitch of the side portions l2 of the blades l0, ll is greater than the pitch of the medial portions l3 of said blades. Moreover, the side portions l2 are of greatest width at the innerends of the blades and gradually decrease in width outwardly, finally merging with the medial portions of the blades near the outer ends of the latter. As the blades rotate, these blade side portions l2 of substantially triangular shape and of increasing width inwardly and of greater pitch at all points in their lengths than the portions of the blades therebetween, serve to produce, toward the inner ends of the blades, progressively greater pressure effects upon the impelled air than is produced by the portions of the blades between said portions I 2. Consequently, a portion of the impelled air is, as aforesaid, directed toward a prolongation of the axis of rotation of the fan, which is of advantage in many instances, as, for example, where it is desired that there shall not be a rapid spreading or difiusion of the impelled air, but that the air shall be impelled in the form of a strong, elongated current of small transverse dimension.

The blades of a fan constructed in accordance with the invention may, as aforesaid, be formed in any suitable manner from any suitable material and may be attached to a hub in any suitable or desired manner. It has been found, however, that the hub and the blades of a fan of the present type may be produced as a one-piece unit very economically and satisfactorily from a single piece of sheet metal or other suitable sheet material by a simple method involving first cutting and slitting a blank of sheet material and then manipulating said blank to provide the hub and the blades of the.fan.

In carrying out the present method a strip S of sheet material of suitable width and length first is cut and slitted as shown in Fig. 8 of the drawings to provide the" blades and the hub of the fan in developed form. In other words, the strip of sheet material is cut and slitted to provide a series of the fan blades H in developed, side to side relationship joined together at their ends by two side marginal, band-like portions l of the strip. The strip then is bent into cylindrical form, either around a mandrel l6 as illustrated'in Fig. 9 of the drawings, orin any other suitable manner, and its ends then are suitably fastened together. The diameter of'the cylinder is, of course, predetermined so that the blades will be evenly spaced therearound. The bandlike portions l5 then are moved toward one another, which results in the blades being bulged outwardly into substantially V-shape, outward bulging of said blades being initiated and controlled in any suitable manner so that when movement of the band-like portions l5 toward one another is completed the blades will have desired final form and desired final disposition relative to each other and to the hub comprised by the two band-like portions l5, as illustrated in Fig. 10 of the drawings. Thereafter, if necessary of desirable, a sleeve may be inserted in the band-like portions l5 and said portions may be fastened to said sleeve in any desired manner to impart increased rigidity, stability and strength to the hub; or, alternatively, any other suitable means in lieu of a sleeve may be employed to securely hold the band-like portions l5 in their final positions. In some cases it may be necessary or desirable to rotate the band-like portions l4 relative to one another to assist in imparting; or in permitting to be imparted, desired shape to the blades, and that procedure is, of course, contemplated by the invention.

From the. foregoing description considered in connection with the accompanying drawings it is believed that the construction and operation of a fan constructed in accordance with the invention, as well as the present advantageous method of producing a fan of the present type, will be clearly understood. It is desired to point out, however, that while only certain specific embodiments of fans constructed in accordance with the invention, and only a single, specific method of producing such a fan, have been illustrated and described, the invention, both in respect to the fan and the method, is not necessarily as herein illustrated and described, but is readily capable of modifications and changes within its spirit and scope as defined in the appended claims.

I claim:

1. A fan comprising a hub and a first series of pairs of blades extending outwardly from said hub, the blades of eachv pair convergingtoward and being joined together at'their outer ends, said blades being disposed diagonally relative to the plane of rotation of the fan, the inner ends of the blades of each pair being spaced apart both forwardly and rearwardly and annularly relativeto said hub, and a second series of pairs of blades duplicating said first series, the forward blades of the rear seriesbeing disposed rearwardly of the forward blades and. forwardly of the rear blades of the forward series, and the rear blades of the forward series being disposed forand being joined together at their outer ends,

said blades being disposed diagonally relative to the plane of rotation of the fan, the inner ends of the blades of each pair being spaced apart both forwardly and rearwardly and annularly relative to said hub, and a second series of pairs of blades duplicating said first series, the forward blades of the rear series being disposed rearwardly of the forward-blades and forwardly of the rear blades of the forward series, and the rear blades of the forward series being disposed forwardly of the rear blades and rearwardly of the forward blades of th rear series, and corresponding blades of the pairs 'of the two series being approximately alined with each other longitudinally of the fan.

3. Afan comprising a hub and pairs of blades extending outwardly from said hub, the blades of each pair converging toward and being joined together at their outer end, said blades being disposed diagonally relative to the plane of rotation of the fan, the inner ends of the blades of each pair being spaced apart both longitudinally and annularly relative to said hub, the pitch of each blade progressively increasing from the outer end of the blade to its inner end.

4. A fan comprising a hub and pairs of blades extending outwardly from said hub, the blades of each pair converging toward and being joined together at their outer ends, said blades being disposed diagonally relative to the plane of rotation of the fan, the inner ends of the blades of each pair being spaced apart both longitudinally and annularly relative to said hub, the pitch of each gether at their outer ends, saidblades being disposed diagonally relative to the plane of rotation of the fan, the inner ends of the blades of each pair being spaced apart both longitudinally and annularly relative to said hub, the pitch of each blade progressively increasing from the outer end of the blade to its inner end, the leadingblade of each pair, as regards the direction of rotation of the fan, being disposed rearwardly of the trailing blade of the next adjacent forwardly-disposed pair of blades, and the leading edges of the leading blades and the trailing edges of the trailing blades intersecting the hub in approximately a common plane parallel to the plane of rotation of the fan.

6. A fan comprising a hub and pairs of blades extending outwardly from said hub, the blades of each pair converging toward and being joined together at their outer ends, said blades being disposed diagonally relative to the plane of rotation of the fan, the inner ends of the blades of each pair being spaced apart both longitudinally and annularly relative to said hub, the side marginal portions of said blades having greater pitch than the portions of said blades between said side marginal portions.

7. A fan comprising a hub and pairs of blades extending outwardly from said hub, the blades of each pair converging toward and being joined together at their outer ends, said blades being disposed diagonally relative to the plane of rotation of the fan, the inner ends of the blades of each pair being spaced apart both longitudinally and annularly relative to said hub, the pitch of each blade progressively increasing from the outer end of the blade to its inner end, and the side marginal portions of said blades having greater pitch than the portions of said blades between said side marginal portions.

8. A fan comprising a hub and pairs of blades.. extending outwardlyfrom said hub, the blades of each pair converging toward and being joined together at their outer ends, said blades being disposed diagonally relative to the plane of rotation of the fan, the inner ends of the blades of each pair being spaced apart both longitudinally and annularly relative to said hub, the side marginal portions of said blades having greater pitch than the portions of said blades between said side marginal portions, the said blade side marginal portions of greater pitch than the blade portions therebetween being of decreasing width toward the outer ends of the blades.

9. A fan comprising a hub and pairs of blades extending outwardly from said hub, the blades of each pair converging toward and being joined together at their outer ends, said blades being disposed diagonally relative to the plane of rotation of the fan, the inner ends of the blades of each pair being spaced apart both longitudinally and annularly relative to said hub, the side marginal portions of said blades having greater pitch than the portions of said blades between said side marginal portions, the said blade side marginal portions of greater pitch than the blade portions therebetween being of decreasing pitch toward the outer ends of the blades.

10. A fan comprising a hub and pairs of blades extending outwardly from said hub, the blades of each pair converging toward and being joined together at their outer ends, said blades being disposed diagonally relative to the plane of rotation of the fan, the inner ends of the blades of each pair being spaced apart both longitudinally and annularly relative to said hub, the side marginal portions of said blades having greater pitch than the portions of said blades between said side marginal portions, the said blade side marginal portions of greater pitch than the blade portions therebctween being of decreasing width and also of decreasing angularity to the plane of rotation of the fan toward the outer ends of the blades.

11. A fan comprising a hub and pairs of blades extending outwardly from said hub, the blades of each pair converging toward and being joined together at their outer ends, said blades being disposed diagonally relative to the plane of rotation of the fan, the inner ends of the blades of each pair being spaced apart both longitudinally and annularly relative to said hub, the pitch of each blade progressively increasing from the outer end of the blade to its inner end, and the side marginal portions of said blades having greater pitch than the portions of said blades between said side marginal portions, the said blade side marginal portions of greater pitch than the blade portions therebetween being of decreasing width toward the outer ends of the blades.

12. A fan comprising a hub and pairs of blades extending outwardly from said hub, the blades of each pair converging toward and being joined together at their outer ends, said blades being disposed diagonally relative to the plane of rotation of the fan, the inner ends of the blades of each pair being spaced apart both longitudinally and annularly relative to said hub, the pitch of each blade progressively increasing from the outer end of the blade to its inner end, and the side marginal portions of'said blades having greater pitch than the portions of said blades between said side marginal portions, the said blade side marginal portions of greater pitch than the blade .portions therebetween being of decreasing pitch toward the outer ends of the blades.

13. A fan comprising a huband pairs ofblades extending outwardly from said hub, the blades of each pair converging toward and'being joined together at their outer ends, said blades being disposed diagonally relative to the plane of rotation of the fan, the inner ends of the blades of each pair being spaced apart both longitudinally and annularly relative to said hub, the pitch of each blade progressively increasing from the outer end of the blade to its inner end, and the side marginal portions of said blades having greater pitch than the portions of said blades between said side marginal portions, the said blade side marginal portions of greater pitch than the blade portions therebetween being of decreasing width and also of decreasing pitch toward the outer ends of the blades.

FRIEDRICH HONERKAMP. 

